Multi-carrier digital mobile multimedia broadcast system and the digital information transmission method thereof

ABSTRACT

The present invention discloses a multi-carrier digital multimedia broadcast system and the digital information transmission method thereof. After RS encoding and byte interleaving, LDPC encoding, bit interleaving and constellation mapping to an upper layer of data streams in turn, the obtained data symbol is multiplexed with scattered pilots and continual pilots which include the system information to form an OFDM frequency domain symbol and scrambled; an OFDM time domain symbol is generated by IFFT transforming, and after inserted with the frame head to build a time slot, it is connected to form a signal frame of the physical layer; the signal frame of the physical layer is transmitted after being low-pass filtered and orthogonal upconverted. The system and method thereof provide wireless broadcast with high quality such as audio, video and multimedia data and the like for mobile, fixed and portable receivers, and can use the satellite transmission and terrestrial transmission method for transmitting. The method utilizes the LDPC OFDM scheme, and the system applies the microwave and large scale integrated circuit technologies while fulfills the needs for low cast and high performance.

TECHNICAL FIELD

The present invention relates to digital information transmission field,and more particularly, to a digital multimedia broadcast system and aninformation transmission method thereof.

BACKGROUND

Besides large coverage and large program capacity, wirelesscommunication broadcasting has a most excellent characteristic of itsbroadcast capability which can be point-to-point and point-to-face, andit has high transmission bandwidth with low cost. Thus, as an importantcomponent of information communication industry, the wirelesscommunication broadcasting plays an important role in the constructionof national information infrastructure and realization of normal serviceand national information security strategy.

With years of research and development, the digital wireless broadcasthas obtained many achievements which reaches practical use stage.Presently, there are 4 wireless digital television broadcast standardsin the world:

1) Digital Video Broadcasting (DVB) Standards Series.

DVB is proposed by European Telecommunications Standards Institute(ETSI). After the Europe stopped development of Digital-to-Analog mixedtelevision system in 1993, it began to undertake research on digitaltelevision broadcast system, and successively issued Digital VideoBroadcasting-Satellite (DVB-S), Digital Video Broadcasting-Cable(DVB-C), Digital Video Broadcasting-Terrestrial (DVB-T) standards andDigital Video Broadcasting-Handheld (DVB-H) standard based on DVB-T.

The DVB-S standard in the above mentioned standards utilizes singlecarrier QPSK modulation, uses cascaded convolution code and RS code aschannel encoding, scrambles with Pseudo-Random Bit Sequence (PRBS), useswireless satellite links, which is only adaptable to fixed receivingsystem rather than mobile terminal devices. The DVB-T standard usesmulti-carrier Orthogonal Frequency Division Multiplexing (OFDM)modulation technology and encoding technology of cascaded convolutioncode and RS code, which is adapted to open-ground transmission, however,the moving speed is low. Although the DVB-H system optimizes formobilization and handheld purpose, the optimization is not sufficientdue to the limitation of DVB-T coding and modulation technology.

2) American ATSC Standard

The American ATSC standard is a single-carrier digital televisionterrestrial transmission standard proposed by Advanced Television Systemcommittee (ATSC), which can support fixed receiving of digitaltelevision with standard definition and high-definition. However, theperformance thereof is inferior under mobile reception condition and cannot support satellite transmission.

3) Japanese ISDB-T Standard

ISDB-T is an Integrated Service Digital Broadcasting-Terrestrialstandard revised by Japan digital broadcasting expert group whichachieves terrestrial broadcasting of various digital services with OFDMtechnology, convolution code and RS code. However, the performancethereof is inferior under mobile reception condition and can not supportsatellite transmission.

4) Japan-Korean Digital Satellite Broadcasting Standard

In May, 1998, Toshiba Corp., SKTelecomm Corp., Sharp Corp., Toyota MotorCorp. etc. jointly invested and founded a Mobile BroadcastingCorporation. And it launched a broadcasting satellite in March, 2004,and now it is running into business, providing services for Japan andKorea. The system also uses PRBS, interleaving concatenated encoding,and it transmits in a manner of CDM frequency spreading. Although theJapan-Korean digital satellite broadcasting standard can support mobilereception, the performance thereof is not sound enough, which needsfurther improvement.

SUMMARY OF INVENTION

To overcome the shortcomings of the four kinds of transmission modesaforementioned, the present invention optimizes design and proposes anintegrated wireless multi-service broadcast system architecture adaptedfor satellite transmission, terrestrial transmission etc., which canprovide for mobile, portable and fixed receiving users with high-qualityaudio, video and multimedia data services.

The present invention provides a multi-carrier digital mobile multimediabroadcast system comprising a transmitter and portable, fixed or mobilereceivers, the transmitter comprising:

a RS encoding and byte interleaving module for RS encoding and byteinterleaving an upper layer data stream;

a LDPC encoder for LDPC encoding the data outputted from the byteinterleaver to obtain bit data;

a bit interleaver for bit interleaving of the bit data outputted fromthe LDPC encoder;

a constellation mapping module, in which the data outputted from the bitinterleaver is constellation mapped;

a frequency-domain symbol generator for multiplexing together discretepilots, continuous pilots containing system information and data symbolsbeing constellation mapped to form an OFDM frequency-domain symbol;

a scrambler for scrambling the OFDM frequency-domain symbol;

an OFDM modulator for performing IFFT transformation to thefrequency-domain symbol outputted from the scrambler to generate an OFDMtime-domain symbol;

a time-domain framing device for concatenating the time slots which areformed with the OFDM time-domain symbols to form a physical layer signalframe.

The system uses wireless channels such as satellite or terrestrialwireless channels etc. mainly for achieving mobile reception. The systemsupports single frequency network and multi-frequency network modes, andit can select corresponding transmission modes and parameters based onthe transmitted data types and networking environments for transmittingvideo streams such as H.264, AVS, MPEG-2, MPEG-4 etc, and audio streamssuch as AC-3, AAC etc., and it supports mixed transmission modes withkinds of data types for transmitting broadcasting data including audiodata, text and video data.

The present invention also provides a digital information transmissionmethod for a multi-carrier digital mobile multimedia broadcast system,comprising the following steps:

RS encoding and byte interleaving an upper layer data stream with a RSencoding and byte interleaveing module, in which the row numbers of thebyte interleaver is determined by a byte interleaving mode and a LDPCcode rate;

LDPC encoding the byte interleaved data by a LDPC encoder to obtain bitdata;

bit interleaving the LDPC encoded bit data by a bit interleaver;

constellation mapping the byte interleaved data by a constellationmapping module;

multiplexing discrete pilots, continuous pilots containing systeminformation and data symbols being constellation mapped by afrequency-domain symbol generator to form an OFDM frequency-domainsymbol;

scrambling the multiplexed OFDM frequency-domain symbol with ascrambler;

performing IFFT transformation to the scrambled frequency-domain symbolto generate an OFDM time-domain symbol by an IFFT transformer;

concatenating the time slots which are formed by inserting a frame headto the time-domain OFDM symbol with a time-domain framing device to forma physical signal frame;

transmitting the physical signal frame after low-pass filtering andorthogonal up-converting.

The digital information transmission method transmits multimediabroadcasting data including audio data, text and video data.

The system adopts an OFDM scheme of LDPC, and the receiver of the systemuses the most advanced technologies of microwave and large scale digitalintegrated circuit which satisfies requirements of low cost and highperformance.

BRIEF DESCRIPTION OF DRAWINGS

The present invention is described but not limited in conjunction withthe embodiments shown in the drawings throughout which the similarreference signs represent the similar elements, in which:

FIG. 1 is a structural view of a physical logical channel of abroadcasting channel in a mobile multimedia broadcast system accordingto some embodiments of the invention;

FIG. 2 is a flow chart of logical channel encoding and modulation of thephysical layer in the mobile multimedia broadcast system according tosome embodiments of the invention;

FIG. 3 is a time slot division and frame structure view of the physicalsignal frame formed by time-slot framing in FIG. 2;

FIG. 4 is a structural view of a beacon in FIG. 3;

FIG. 5 is a schematic structural view of a pseudo-random sequencegenerator of a synchronous signal;

FIG. 6 is a structural view of the OFDM symbol in FIG. 3;

FIG. 7 is a schematic view of overlapping between guard intervals;

FIG. 8 is a structural schematic view of an OFDM symbol;

FIG. 9 is a schematic view of a byte interleaver with RS (240, K)encoding;

FIG. 10 is a schematic view of bit interleaving to the bit stream beingLDPC encoded;

FIGS. 11, 12 and 13 are BPSK constellation mapping view, QPSKconstellation mapping view and 16 QAM constellation mapping viewrespectively;

FIG. 14 is a pilot multiplexing schematic view of allocatingsub-carriers of the OFDM symbol to the data symbol, discrete pilot andcontinuous pilot;

FIG. 15 is a schematic view of a generating method for PRBS; and

FIG. 16 is a schematic view of a sub-carrier structure of the OFDMsymbol.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention can provide multimedia programs including highquality digital audio broadcasting and digital video broadcasting.

The present invention defines functional modules of the physical layerwhich can perform adaptive processing to the broadcasting upper layerdata stream of the mobile multimedia broadcast system within 8 MHzbandwidth, and it discloses frame structure, channel encoding andmodulation technologies of the transmission signals in the physicallayer of the mobile multimedia broadcast channel.

The physical layer is an under layer of OSI which is fundamental to thewhole open system. The physical layer provides transmission media andinterconnecting devices for data communication between devices andprovides reliable environments for data transmission.

The physical layer of broadcast channel defined in the present inventionmeets different transmission rates for various applications of the upperlayers by the physical logical channels. The physical logical channelssupport various encoding and modulating manners to satisfy differentrequirements of different applications, different transmissionenvironments to signal quality.

The physical layer of the broadcast channel defined in the presentinvention supports two kinds of networking modes, i.e., a singlefrequency network and a multi-frequency network. And differenttransmission modes and parameters can be selected based on actuallyapplication characteristics and networking environments. And mixed modeof various applications is provided to match the applicationcharacteristics with the transmission mode, thus achieving flexibilityand economy of applications.

The preferred embodiment of the invention will be described in detailwith reference to accompanying figures.

FIG. 1 is a structural view of a physical logical channel of abroadcasting channel in a mobile multimedia broadcast system accordingto some embodiments of the invention.

As shown in the Figure, the physical layer provides a broadcast channelfor upper layer application by a physical logical channel, i.e., PLCH,which includes a control logic channel (CLCH) and a service logicchannel (SLCH). Each physical logical channel can use one or more oftime slots in the 8 MHz digital television bandwidth for transmission.The physical layer performs separate encoding and modulation for eachphysical logical channel. The physical logical channel can providedifferent transmission capacity with different encoding and modulatingparameters.

FIG. 2 is a flow chart of logical channel encoding and modulation of thephysical layer in the mobile multimedia broadcast system according tosome embodiments of the invention.

As shown in the figure, the inputted, data stream of the physicallogical channel undertakes OFDM modulation by multiplexing together withdiscrete pilot and continuous pilot after forward correction encoding,interleaving and constellation mapping. The modulated signal forms aphysical signal frame after being inserted with a frame head. And thesignal is transmitted after being transformed from baseband to RF(radio-frequency).

The physical logical channel is divided into the control logical channel(CLCH) and the service logical channel (SLCH). The control logicalchannel carries system configuration information, and uses a fixedchannel encoding and modulation model to transmit at the 0th time slotof the system, in which: RS encoding uses RS(240, 240), the LDPCencoding uses LDPC encoding with ½ code rate, the constellation mappinguses BPSK mapping, the scramble mode adopts mode 0. The service logicalchannel can use one or more time slots except the 0^(th) time slot fortransition, and the encoding and modulation mode thereof are configuredby the upper layers, the configuration information is broadcastedthrough the control logical channel.

The sub-modules in FIG. 2 will be described in detail in the following.

FIG. 3 is a time slot division and frame structure view of the physicalsignal frame formed by time-slot framing in FIG. 2.

As shown in the figure, each second represents 1 frame in the signal ofthe physical layer of the system, and each frame is divided into 40 timeslots (TS), with each time slot having a length of 25 ms.

Each time slot comprises a beacon and 53 OFDM modulating data blocks.

FIG. 4 is a structural view of a beacon in FIG. 3.

As shown in the figure, the beacon has two same synchronous signals anda transmitter identification signal (ID).

The synchronous signal is a pseudo-random sequence with a limitedfrequency band, having a length of 204.8 us. The synchronous signal isgenerated as follows: firstly, the pseudo-random sequence is generatedby a pseudo-random sequence generator for synchronous signal as shown inFIG. 5, as shown in the figure, the polynomial for generating thepseudo-random sequence is x11+x9+1, with preset value of 01110101101;then the former 1538 points are extracted from the m-sequence with 2047points, after BPSK mapping (0→1+0j, 1→−1+0j), they are put into the1th˜769th and 1279th˜2047th points within the 2048-point (0˜2047)sequence; and a synchronous signal is obtained after the generated2048-point of sequence being subjected to IFFT.

The transmitter identification signal (ID) transmits a pseudo-randomsequence with limited frequency-band having a length of 36 us foridentifying different transmitter. The generating method of thetransmitter identification signal is as follows:

Selecting a transmitter identification sequence; after BPSK mapping(0→1+0j, 1→−1+0j) of the 191-point transmitter identification sequence,they are putted into the 1th˜95th and 160th˜255th points in the256-point (0˜255) sequence; after the 256 point being subjected to IFFTand extending the period to 360 points, thus obtaining the transmitteridentification signal.

The transmitter identification sequence is a pseudo-random sequence witha length of 191 bits. The transmitter identification sequence includes256 sequences in total in which the 0^(th)˜127^(th) sequence designatesdistrict identification for identifying location of the transmitter, andit is inserted and transmitted by the even time-slots in the signalframe (the 0^(th) time slot, the second time slot, . . . ); the128^(th)˜255^(th) sequence designates the identification of atransmitter for identifying different transmitters in a same district,which is inserted and transmitted by the odd time-slots in the signalframe (the first time-slot, the third time-slot, . . . ). Thetransmitter identification sequence is defined by a hex sequence whichis mapped to a binary transmitter identification sequence in an orderthat the highest effective bit first to enter into the BPSK mappingstep. The transmitter identification sequences are shown as in Table 1.

TABLE 1 transmitter identification sequence No. transmitteridentification sequence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

FIG. 6 is a structural view of the OFDM symbol in FIG. 3.

As shown in the figure, the OFDM symbol comprises a circular prefix (CP)and an OFDM symbol body, the length TCP of the circular prefix is 51.2us, the length TS of the OFDM symbol is 409.6 us.

The transmitter identification signal, the synchronous signal and theneighboring OFDM symbol in FIG. 3 are overlapped with guard intervals(GD). The length TGD of the guard interval GD is 2.4 us. An end part GDof a former symbol and a head part GD of a latter symbol in theneighboring symbols are overlapped after weighting with a windowfunction, as shown in FIG. 7.

The expression of the window function is as follows:

${w(t)} = \left\{ \begin{matrix}{{0.5 + {0.5\;{\cos\left( {\pi + {\pi\;{t/T_{GD}}}} \right)}}},} & {0 \leq t \leq T_{GD}} \\{1,} & {T_{GD} < t < {T - T_{GD}}} \\{{0.5 + {0.5\;{\cos\left( {\pi + {{\pi\left( {T - t} \right)}/T_{GD}}} \right)}}},} & {{T - T_{GD}} \leq t \leq T}\end{matrix} \right.$

The selection of the guard interval signals is as shown in FIG. 8. Forthe transmitter identification signal, the synchronous signal and theOFDM symbol, the value of the T0 and T1 are as shown in Table 2.

TABLE 2 the value table of the guard interval signal signal T0 (us) T1(us) transmitter 25.6 10.4 identification signal Synchronous 409.6 0signal OFDM symbol 409.6 51.2

The sub-systems in FIG. 2 will be described in detail in the follows.

FIG. 9 is a schematic view of a byte interleaver with RS (240, K)encoding.

As shown in the figure, the byte interleaver is a block interleaver withM1 rows and 240 columns. The row number M1 of the byte interleaver isdetermined by the byte interleaving mode and the LDPC code rate as shownin Table 3:

TABLE 3 the value table of the parameter M1 of the byte interleaverInterleaving Interleaving Interleaving mode 1 mode 2 mode 3 1/2 MI = 72 MI = 144 MI = 288 LDPC code 3/4 MI = 108 MI = 216 MI = 432 LDPC code

The RS code adopts a RS(240, K) shortened code with a code length of 240bytes. The code is generated by shortening the original RS(255, M)system code, in which M=K+15 where K is the byte number of informationsequence in a code word while the check byte number is (240-K). TheRS(240, K) code provides 4 kinds of modes with K values of K=240, K=224,K=192 and K=176 respectively.

Each code bit of the RS(240, K) code is picked from a domain GF(256)which has a generating polynomial p(x)=x⁸+x⁴+x³+x²+1.

The shortened code RS (240, K) is encoded as follows:

15 full “0” byte are added in front of K input information bytes (m₀,m₁, . . . , m_(K-1)), thus an input sequence (0, . . . 0, m₀, m₁, . . ., m_(K-1)) as the original RS (255, M) system code is constructed, afterencoding the generated code word is (0, . . . , 0, m₀, m₁, . . . ,m_(K-1), p₀, p₁, . . . , p_(255-M-1)), then the added bytes are removedfrom the code word, thus obtaining a code word (m₀, m₁, . . . , m_(K-1),p₀, p₁, . . . , p_(255-M-1)) as a shortened RS code with 240 bytes.

The expression of the generating polynomial of the RS (240, K) code isas follows:

${{g(x)} = {\sum\limits_{i = 0}^{240 - K}{g_{i}x^{i}}}},$

The expression of the inputted information sequence polynomial is asfollows:

${{m(x)} = {\sum\limits_{i = 0}^{K - 1}{m_{i}x^{i}}}},$

The expression of the outputted system code polynomial is as follows:

${C(x)} = {{\sum\limits_{i = 0}^{239}{c_{i}x^{i}}} = {{{x^{240 - K}{m(x)}} + {{r(x)}\mspace{14mu}{in}\mspace{14mu}{which}\mspace{14mu}{r(x)}}} = \frac{x^{240 - K}{{gm}(x)}}{g(x)}}}$

The coefficients g_(i) of the generated polynomial expression of the RS(240, 224) are as follows:

i g_(i) 0 79 1 44 2 81 3 100 4 49 5 183 6 56 7 17 8 232 9 187 10 126 11104 12 31 13 103 14 52 15 118 16 1

The coefficients g_(i) of the generated polynomial expression of the RS(240, 192) are as follows:

i g_(i) 0 228 1 231 2 214 3 81 4 113 5 204 6 19 7 169 8 10 9 244 10 11711 219 12 130 13 12 14 160 15 151 16 195 17 170 18 150 19 151 20 251 21218 22 245 23 166 24 149 25 183 26 109 27 176 28 148 29 218 30 21 31 16132 240 33 25 34 15 35 71 36 62 37 5 38 17 39 32 40 157 41 194 42 73 43195 44 218 45 14 46 12 47 122 48 1

The coefficients g_(i) of the generated polynomial expression of the RS(240, 176) are as follows:

i g_(i) 0 106 1 117 2 43 3 201 4 70 5 139 6 47 7 64 8 127 9 181 10 48 1125 12 230 13 85 14 31 15 157 16 156 17 123 18 88 19 44 20 149 21 223 22165 23 36 24 127 25 46 26 142 27 212 28 233 29 71 30 149 31 88 32 165 33227 34 80 35 105 36 44 37 72 38 147 39 55 40 60 41 85 42 70 43 132 44229 45 230 46 217 47 155 48 38 49 112 50 43 51 174 52 169 53 136 54 2355 60 56 186 57 63 58 198 59 205 60 135 61 171 62 40 63 159 64 1

The method of encoding and the byte interleaving is as follows: datablock is transmitted by byte, and inputted into the block interleaverfrom left to right column by column until the Kth column with eachcolumn having MI bytes. The RS encoding is performed by row, and theverifying bytes are filled to the latter (240-K) columns. The encodeddata is outputted from left to right column by column as the order ofinputting until all 240 columns are finished.

The above RS encoding and the byte interleaving are undertaken based onphysical logical channels. The upper layer packages of the same physicallogical channel are inputted into the byte interleaver in turn for byteinterleaving and RS encoding. The first byte of the 0^(th) column in thebyte interleaver is defined as a start byte of the byte interleaver.Each output of the byte interleaver (M1×240 bytes) are always mapped toa integer number of time slots to be transmitted, in which the startbyte of the byte interleaver is mapped to a start point of a certaintime slot to be transmitted.

After the RS encoding and byte interleaving, the transmission data istransmitted based on the rule of bit of higher order having higherpriority for transmitting, and each byte is mapped to form a 8-bitstream to be transmitted into the LDPC encoder. The first byte of the0^(th) column in the byte interleaver is defined as the start byte ofthe byte interleaver with the bit of highest order being mapped to thefirst bit of the LDPC inputting bit block. The LDPC encodingconfiguration is shown in Table 4:

TABLE 4 LDPC encoding configuration Code The length of the The length ofthe rate inputted block outputted block 1/2 4608 bits 9216 bits 3/4 6912bits 9216 bits

The LDPC encoding is given by a check matrix H, and the generatingmethod of the matrix H is as follows:

$\left. 1 \right)\mspace{14mu} a\mspace{14mu}{generating}\mspace{14mu}{method}\mspace{14mu}{of}\mspace{20mu} a\mspace{14mu}\frac{1}{2}{LDPC}\mspace{14mu}{code}\mspace{14mu}{check}\mspace{14mu}{matrix}$0 6 12 18 25 30 0 7 19 26 31 5664 0 8 13 20 32 8270 1 6 14 21 3085 89591 15 27 33 9128 9188 1 9 16 34 8485 9093 2 6 28 35 4156 7760 2 10 177335 7545 9138 2 11 22 5278 8728 8962 3 7 2510 4765 8637 8875 3 46534744 7541 9175 9198 3 23 2349 9012 9107 9168 4 7 29 5921 7774 8946 47224 8074 8339 8725 9212 4 4169 8650 8780 9023 9159 5 8 6638 8986 90649210 5 2107 7787 8655 9141 9171 5 24 5939 8507 8906 9173

The following is a circular program segment for generating the

$\frac{1}{2}$LDPC code check matrix:for I=1:18;

using the I^(th) row of the above table, and being designated as hexp;

for J=1:256;

-   -   row=(J−1)*18+I;    -   for K=1:6;        column=[(└hexp(K)/36┘+J−1)% 256]*36+(hexp(K)%36)+1.

The row^(th) row and the column^(th) column of the parity check matrixbeing non-zero elements;

end; end; end;

2) a generating method of a

$\frac{3}{4}$LDPC code check matrix

0 3 6 12 16 18 21 24 27 31 34 7494 0 4 10 13 25 28 5233 6498 7018 83588805 9211 0 7 11 19 22 6729 6831 7913 8944 9013 9133 9184 1 3 8 14 17 2029 32 5000 5985 7189 7906 1 9 4612 5523 6456 7879 8487 8952 9081 91299164 9214 1 5 23 26 33 35 7135 8525 8983 9015 9048 9154 2 3 30 3652 40675123 7808 7838 8231 8474 8791 9162 2 35 3774 4310 6827 6917 8264 84168542 8834 9044 9089 2 15 631 1077 6256 7859 8069 8160 8657 8958 90949116

The following a is a circular program segment for generating the

$\frac{3}{4}$LDPC code check matrix:

for I=1:9;

using the I^(th) row of the above table, and being designated as hexp;

for J=1:256;

-   -   row=(J−1)*9+I;    -   for K=1:12;        column=[(└hexp(K)/36┘J−1)%256]*36+(hexp(K)%36)+1.

The row^(th) row and the column^(th) column of the parity check matrixbeing non-zero elements;

end; end; end;

FIG. 10 is a schematic view of bit interleaving to the bit stream being

LDPC encoded.

As shown in the figure, the bit interleaver uses a 384×360 blockinterleaver. The LDPC encoded binary sequence is written into each rowof the block interleaver in turn in the order from up to low until thewhole interleaver is filled up, then it is read from left to right inturn based on column. The output of the bit interleaver is aligned withthe time slot, i.e., the first bit transmitted in each time slot isalways defined as the first bit outputted from the bit interleaver.

FIGS. 11, 12 and 13 are BPSK constellation mapping view, QPSKconstellation mapping view and 16 QAM constellation mapping viewrespectively. The power normalization factors corresponding to the BPSK,QPSK and 16 QAM constellation mapping are 1/√{square root over (2)},1/√{square root over (2)}, 1/√{square root over (10)} respectively.

FIG. 14 is a pilot multiplexing schematic view of allocatingsub-carriers of the OFDM symbol to the data symbol, discrete pilot andcontinuous pilot.

As shown in the figure, the part of oblique line is a continuous pilotsignal, the black part is a discrete pilot signal, the white part isdata obtained by constellation mapping. The pilot multiplexing proceduremultiplexes the data symbol, the discrete pilot and the continuouspilot, forming an OFDM frequency-domain symbol. Each OFDM symbolcomprises 3076 sub-carriers (0-3075), denoting as X(i), i=0, 1, . . .3075.

In FIG. 15, the continuous pilots use the 0th, 22th, 78th, 92th, 168th,174th, 244th, 274th, 278th, 344th, 382th, 424th, 426th, 496th, 500th,564th, 608th, 650th, 688th, 712th, 740th, 772th, 846th, 848th, 932th,942th, 950th, 980th, 1012th, 1066th, 1126th, 1158th, 1214th, 1244th,1276th, 1280th, 1326th, 1378th, 1408th, 1508th, 1537th, 1538th, 1566th,1666th, 1736th, 1748th, 1794th, 1798th, 1830th, 1860th, 1916th, 1948th,2008th, 2062th, 2094th, 2124th, 2132th, 2142th, 2226th, 2228th, 2302th,2334th, 2362th, 2386th, 2424th, 2466th, 2510th, 2574th, 2578th, 2648th,2650th, 2692th, 2730th, 2796th, 2800th, 2830th, 2900th, 2906th, 2982th,2996th, 3052th, 3075th sub-carriers, 82 in total.

The 22th, 78th, 92th, 168th, 174th, 244th, 274th, 278th, 344th, 382th,424th, 426th, 496th, 500th, 564th, 608th, 650th, 688th, 712th, 740th,772th, 846th, 848th, 932th, 942th, 950th, 980th, 1012th, 1066th, 1126th,1158th, 1214th, 1860th, 1916th, 1948th, 2008th, 2062th, 2094th, 2124th,2132th, 2142th, 2226th, 2228th, 2302th, 2334th, 2362th, 2386th, 2424th,2466th, 2510th, 2574th, 2578th, 2648th, 2650th, 2692th, 2730th, 2796th,2800th, 2830th, 2900th, 2906th, 2982th, 2996th, 3052th carriers, 64 intotal, carry 16 bit system information. The system information bits aretransmitted by 4 times repeat encoding to be mapped to 4 continuouspilots. The mapping relationship is shown in Table 5, the detailedexpression of the system information is shown in Table 6, with theremaining continuous pilots transmitting “0”.

TABLE 5 the repeat encoding manner on continuous pilot bit Numberingwith sub-carrier 0 22, 650, 1860, 2466 1 78, 688, 1916, 2510 2 92, 712,1948, 2574 3 168, 740, 2008, 2578 4 174, 772, 2062, 2648 5 244, 846,2094, 2650 6 274, 848, 2124, 2692 7 278, 932, 2132, 2730 8 344, 942,2142, 2796 9 382, 950, 2226, 2800 10 424, 980, 2228, 2830 11 426, 1012,2302, 2900 12 496, 1066, 2334, 2906 13 500, 1126, 2362, 2982 14 564,1158, 2386, 2996 15 608, 1214, 2424, 3052

TABLE 6 system information transmitted on continuous pilot BitInformation 0~5  Time slot 6 Bit interleaver synchronous identification7 Control logical channel modify indication 8~15 reserved

Each bit in table 6 contains the following information:

1) bit.0˜bit 5 are the current time slot number ranging from 0 to 39;

2) bit 6 is the bit interleaver synchronous identification, when the bitis “1”, the current time slot is identified as the start time slot ofthe byte interleaver;

3) bit 7 is a control logical channel modify indication which indicatesmodification of the terminal's control logical channel configurationinformation by differential modulation. The differential modulation isas follows: supposing the bit 7 in the former frame transmitting a (zeroor 1), and the system control channel configuration information will bemodified in the next frame, the ā is transmitted in the current frameand remains until next modification.

4) bit 8˜bit 15 are reserved.

The continuous pilots are mapped to the sub-carriers in the manner of0→√{square root over (2)}/2+√{square root over (2)}/2j, 1→−√{square rootover (2)}/2−√{square root over (2)}/2j. The same continous sub-carrierpoints of different OFDM symbols in the same time slot transmit the samesymbols.

The number OFDM symbol in each time slot is designated as n, 0≦n≦52; mis the sub-carrier number corresponding to the discrete pilot in eachOFDM symbol, and m is:

${{{if}\mspace{14mu}{{mod}\left( {n,2} \right)}}=={0\mspace{14mu} m}} = \left\{ {{{\begin{matrix}{{{8\; p} + 1},} & {{p = 0},1,2,\ldots\mspace{14mu},191} \\{{{8p} + 3},} & {{p = 192},193,194,\ldots\mspace{14mu},383}\end{matrix}{if}\mspace{14mu}{{mod}\left( {n,2} \right)}}=={1\mspace{14mu} m}} = \left\{ \begin{matrix}{{{8p} + 5},} & {{p = 0},1,2,\ldots\mspace{14mu},191} \\{{{8p} + 7},} & {{p = 192},193,194,\ldots\mspace{14mu},383}\end{matrix} \right.} \right.$

All discrete pilots are set to 1+0j.

In FIG. 14, data signals are mapped in the order of sub-carriers, OFDMsymbols. In the 138330 data sub-carriers of each time-slot, the former138240 sub-carriers carry the complex symbols outputted from the symbolinterleaver, and the latter 90 symbols being filled with zero.

All symbols (effective sub-carriers) on the time-frequency grid of FIG.14 comprise data sub-carriers, discrete pilots and continuous pilotsetc., which are scrambled by the same complex pseudo-random sequenceP_(c)(i). The generating manner of the complex pseudo-random sequenceP_(c)(i) is as follows:

${P_{c}(i)} = {\frac{\sqrt{2}}{2}\left\lbrack {\left( {1 - {2{S_{i}({\mathbb{i}})}}} \right) + {j\left( {1 - {2{S_{q}({\mathbb{i}})}}} \right)}} \right\rbrack}$

in which S_(i)(i) and S_(q)(i) are binary pseudo-random sequences(PRBS).

FIG. 15 is a schematic view of the PRBS generating method.

As shown in the Figure, the PRBS generating polynomial is:x12+x11+x8+x6+1 which is corresponding to the shift register structureshown in the figure. The initial value of the shift register isdetermined by scrambling mode with the corresponding relationships asfollows:

1) scrambling mode 0: initial value 0000 0000 0001

2) scrambling mode 1: initial value 0000 1001 0011

3) scrambling mode 2: initial value 0000 0100 1100

4) scrambling mode 3: initial value 0010 1011 0011

5) scrambling mode 4: initial value 0111 0100 0100

6) scrambling mode 5: initial value 0100 0100 1100

7) scrambling mode 6: initial value 0001 0110 1101

8) scrambling mode 7: initial value 1010 1011 0011

PRBS is reset at the start of each time-slot, all time slots beingscrambled by the same pattern of scrambling code.

The scrambling code is obtained by complex multiplication of the complexsymbol on the effective sub-carriers with the complex pseudo-randomsequence P_(c)(i), the expression of the scrambling code is as follows:Y _(n)(i)=X _(n)(i)×P _(c)(n×3076+i), 0≦i≦3075, 0n≦52

in which the X_(n)(i) is the i^(th) effective sub-carrier on the n^(th)OFDM symbol in each time slot before scrambling and the Y_(n)(i) is theeffective sub-carrier after scrambling.

FIG. 16 is a schematic view of a sub-carrier structure of the OFDMsymbol.

The OFDM sub-carriers X(i), i=0, 1, . . . , 3075 after being insertedwith pilot and scrambled generate an OFDM time-domain symbol aftersubjected to IFFT transformation. The IFFT transforming manner is asfollows:

${{y(t)} = {\frac{1}{\sqrt{4096}}{\sum\limits_{n = 0}^{4095}{{Y(n)}{\mathbb{e}}^{{j2\pi}\frac{{nf},t}{4096}}}}}},{0 \leq t \leq {409.6\mspace{11mu}{us}}},{f_{s} = {10\mspace{14mu}{MHz}}}$

In which

${Y(n)} = \left\{ \begin{matrix}{{X\left( {n - 1} \right)},} & {1 \leq n \leq 1538} \\{{X\left( {n - 1020} \right)},} & {2558 \leq n \leq 4095} \\{0,} & {n = {{0\mspace{14mu}{or}\mspace{14mu} 1539} \leq n \leq 2557}}\end{matrix} \right.$

The OFDM symbol after IFFT transformation is added with circular prefix(CP) to form a time-domain OFDM symbol as shown in FIG. 6.

The modulated OFDM symbol is added with guard intervals, synchronoussignal, and transmitter identification signal in turn according to theframe structure as shown in FIG. 3 to form a time-slot. And then 40time-slots are concatenated to form a physical signal frame.

The time-domain shaping filter used in the system is a FIR filtersatisfying ripple attenuation <1 dB within the bandwidth of a signal andattenuation >40 dBc outside the bandwidth thereof. The frequencybandwidth is 8 MHz which is compatible with conventional analogtelevision bandwidth. The system sampling rate is 10 MHz, and the signalbandwidth of each channel is 7.512 MHz.

The data stream of the upper layer of the system can adopt video streamsincluding H.264, AVS, MPEG-2, MPEG-4 etc, audio streams such as AC-3,AAC etc and other various types of data formats. Encoding data canincludes various types of broadcast data including single medium (suchas video source encoding, text) and multimedia (mixture of audio, video,text and data).

Although the present invention is described in conjunction with theexamples and embodiments, the present invention is not intended to belimited thereto. On the contrary, the present invention obviously coversthe various modifications and may equivalences, which are all enclosedin the scope of the following claims.

What is claimed is:
 1. A multi-carrier digital mobile multimediabroadcast system comprising a transmitter and a receiver, thetransmitter comprising: a RS encoding and byte interleaving module forRS encoding and byte interleaving an upper layer data stream based on aphysical logical channel; a LDPC encoder for LDPC encoding the dataoutputted from the RS encoding and byte interleaving module to obtainbit data; a bit interleaver for bit interleaving the bit data outputtedfrom the LDPC encoder; a constellation mapping module, in which the dataoutputted from the bit interleaver is constellation mapped; afrequency-domain symbol generator for multiplexing together a discretepilot, a continuous pilot containing system information and data symbolbeing constellation mapped to form an OFDM frequency-domain symbol; ascrambler for scrambling the OFDM frequency-domain symbol usingpseudo-random sequence; an IFFT transformer for performing IFFTtransformation to the frequency-domain symbol outputted from thescrambler to generate an OFDM time-domain symbol; and a time-domainframing device for adding a beacon in formt of the OFDM time-domainsymbol to form a time slot and concatenating the time slots to form aphysical signal frame, the beacon comprising a transmitteridentification signal and synchronous sequences, the transmitteridentification signal being obtained by performing BPSK mapping, IFFTtransforming and circular extending with the frequency-domain randomsequence in turn.
 2. The multi-carrier digital mobile multimediabroadcast system according to claim 1, wherein the system uses any 8 MHzbandwidth in a wireless channel and is compatible with the bandwidth ofconventional analog television.
 3. The multi-carrier digital mobilemultimedia broadcast system according to claim 1, wherein the samplingrate of the system is 10 MHz, and the signal bandwidth of each channelis 7.512 MHz.
 4. The multi-carrier digital mobile multimedia broadcastsystem according to claim 1, wherein the upper layer data stream of thesystem comprises data stream including a video stream of H.264, AVS,MPEG-2 or MPEG-4 and an audio stream of AC-3 or AAC.
 5. Themulti-carrier digital mobile multimedia broadcast system according toclaim 1, wherein the system is mainly used for mobile receiving.
 6. Themulti-carrier digital mobile multimedia broadcast system according toclaim 1, wherein the system supports single frequency network andmulti-frequency network modes.
 7. The multi-carrier digital mobilemultimedia broadcast system according to claim 1, wherein the systemselects transmission mode and parameters based on the type oftransmitted data and networking environments.
 8. The multi-carrierdigital mobile multimedia broadcast system according to claim 1, whereinthe system provides a mixed transmission mode having a variety of datatypes.
 9. The multi-carrier digital mobile multimedia broadcast systemaccording to claim 1, wherein the physical logical channel includes acontrol logical channel and a service logical channel.
 10. A digitalinformation transmission method for a multi-carrier digital mobilemultimedia broadcast system, comprising following steps: RS encoding andbyte interleaving an upper layer data stream with a RS encoding and byteinterleaving module based on a physical logical channel, in which rownumbers of module is determined by a byte interleaving mode and a LDPCcode rate; LDPC encoding the byte interleaved data by a LDPC encoder toobtain bit data; bit interleaving the LDPC encoded bit data by a bitinterleaver; constellation mapping the bit interleaved data by aconstellation mapping module; multiplexing together discrete pilots,continuous pilots containing system information and data symbols beingconstellation mapped by a frequency-domain symbol generator to form anOFDM frequency-domain symbol; scrambling the multiplexed OFDMfrequency-domain symbol with a scrambler using a pseudo-random sequence;performing IFFT transformation to the scrambled frequency-domain symbolto generate an OFDM time-domain symbol by an IFFT transformer;concatenating the times slots which are formed by inserting a beacon tothe time-domain OFDM symbol with a time-domain framing device to form aphysical signal frame, the beacon comprising a transmitteridentification signal and synchronous sequences; and transmitting thephysical signal frame after low-pass filtering and orthogonalup-converting.
 11. The digital information transmission method accordingto claim 10, wherein the method uses any 8 MHz bandwidth in a wirelesschannel and is compatible with the bandwidth of conventional analogtelevision.
 12. The digital information transmission method according toclaim 10, wherein the sampling rate of the method is 10 MHz, and thesignal bandwidth of each channel is 7.512 MHz.
 13. The digitalinformation transmission method according to claim 10, wherein the upperlayer data stream of the system comprises data stream including a videostream of H.264, AVS, MPEG-2 or MPEG-4 and an audio stream of AC-3 orAAC.
 14. The digital information transmission method according to claim10, wherein the method is mainly used for mobile receiving.
 15. Thedigital information transmission method according to claim 10, whereinthe method supports single frequency network and multi-frequency networkmodes.
 16. The digital information transmission method according toclaim 10, wherein the method selects transmission mode and parametersbased on the type of transmitted data and networking environments. 17.The digital information transmission method according to claim 10,wherein the method provides a mixed transmission mode having a varietyof data types.
 18. The digital information transmission method accordingto claim 10, wherein the physical logical channel includes a controllogical channel and a service logical channel.
 19. The digitalinformation transmission method according to claim 10, wherein the upperlayer data stream is composed of frames.
 20. The digital informationtransmission method according to claim 10, wherein a length of the frameis 1 second.
 21. The digital information transmission method accordingto claim 19, wherein each frame comprises 40 time slots each having alength of 25 ms.
 22. The digital information transmission methodaccording to claim 10, wherein the physical logical channel istransmitted in one or more time slots.
 23. The digital informationtransmission method according to claim 21, wherein the time slot has abeacon and 53 OFDM symbols.
 24. The digital information transmissionmethod according to claim 10, wherein the beacon comprises a transmitteridentification signal and 2 same synchronous sequences.
 25. The digitalinformation transmission method according to claim 24, whereintransmitter identification signal is obtained from a 191-pointfrequency-domain random sequence by subjecting to BPSK mapping,256-point IFFT transforming and then extending from 104 points to 360points.
 26. The digital information transmission method according toclaim 24, wherein the synchronous sequence is obtained by subjecting toBPSK mapping and IFFT transforming in turn after extracting thefrequency-domain random sequence.
 27. The digital informationtransmission method according to claim 26, wherein the frequency-domainrandom sequence is generated by a linear feedback shift register, and aninitial value of the shift register is 01110101101, and the generatingpolynomial is x¹¹+x⁹+1.
 28. The digital information transmission methodaccording to claim 27, wherein the frequency-domain random sequence isobtained by: extracting 1538 points from the sequence generated by theshift register, and performing BPSK mapping and 2048-point IFFTtransforming in turn.
 29. The digital information transmission methodaccording to claim 24, wherein the transmitter identifier, thesynchronous sequence and the OFDM symbol are overlapped by guardintervals having window function as follows:${w(t)} = \left\{ \begin{matrix}{{0.5 + {0.5\;{\cos\left( {\pi + {\pi\;{t/T_{GD}}}} \right)}}},} & {0 \leq t \leq T_{GD}} \\{1,} & {T_{GD} < t < {T - T_{GD}}} \\{{0.5 + {0.5\;{\cos\left( {\pi + {{\pi\left( {T - t} \right)}/T_{GD}}} \right)}}},} & {{T - T_{GD}} \leq t \leq T}\end{matrix} \right.$ Where t is the time variable, T is a constant, TGDis a length of the guard interval.
 30. The digital informationtransmission method according to claim 29, wherein the length of theguard interval is 24 points.
 31. The digital information transmissionmethod according to claim 10, wherein the OFDM symbol is composed of anOFDM symbol body and a circular prefix.
 32. The digital informationtransmission method according to claim 31, wherein the length of theOFDM body is 4096 points, and the length of the circular prefix is 512points.
 33. The digital information transmission method according toclaim 10, wherein the RS encoding is a RS (240, K) shortening codegenerated by shortening an original RS (255, M) system code, whereM=K+15, and K, M are information bit lengths.
 34. The digitalinformation transmission method according to claim 33, wherein each codebit of the RS (255, M) system code is chosen from a domain GF(256), thegenerating polynomial of the domain is p(x)=x⁸+x⁴+x³+x²+1.
 35. Thedigital information transmission method according to claim 33, whereinthe RS(240, K) includes 4 modes with K in the four modes having thefollowing values respectively: K=240, K=224, K=192 and K=176.
 36. Thedigital information transmission method according to claim 33, whereinthe expression of the generating polynomial of the RS(240, K) is${g(x)} = {\sum\limits_{i = 0}^{240 - K}{g_{i}{x^{i}.}}}$
 37. Thedigital information transmission method according to claim 35, whereincoefficients g_(i) of the generated polynomial expression of the RS(240, 224) are as follows when K=224: i gi 0 79 1 44 2 81 3 100 4 49 5183 6 56 7 17 8 232 9 187 10 126 11 104 12 31 13 103 14 52 15 118 16 1

The coefficients g_(i) of the generated polynomial expression of the RS(240, 192) are as follows where K=192: i gi 0 228 1 231 2 214 3 81 4 1135 204 6 19 7 169 8 10 9 244 10 117 11 219 12 130 13 12 14 160 15 151 16195 17 170 18 150 19 151 20 251 21 218 22 245 23 166 24 149 25 183 26109 27 176 28 148 29 218 30 21 31 161 32 240 33 25 34 15 35 71 36 62 375 38 17 39 32 40 157 41 194 42 73 43 195 44 218 45 14 46 12 47 122 48 1

The coefficients g_(i) of the generated polynomial expression of the RS(240, 176) are as follows where K=176: i gi 0 106 1 117 2 43 3 201 4 705 139 6 47 7 64 8 127 9 181 10 48 11 25 12 230 13 85 14 31 15 157 16 15617 123 18 88 19 44 20 149 21 223 22 165 23 36 24 127 25 46 26 142 27 21228 233 29 71 30 149 31 88 32 165 33 227 34 80 35 105 36 44 37 72 38 14739 55 40 60 41 85 42 70 43 132 44 229 45 230 46 217 47 155 48 38 49 11250 43 51 174 52 169 53 136 54 23 55 60 56 186 57 63 58 198 59 205 60 13561 171 62 40 63 159 64
 1.


38. The digital information transmission method according to claim 10,wherein the upper layer data stream is input into RS encoding and byteinterleaving module column by column in byte, wherein the RS encoding isperformed by rows, a start byte of the byte interleaving module ismapped to be transmitted on a start point of a certain time slot. 39.The digital information transmission method according to claim 10,wherein the length of the outputted block after LDPC encoding is 9216bits with code rates of ½ and ¾ respectively; Wherein the generatingsteps of the $\frac{1}{2}$  LDPC code check matrix is as follows:Firstly constructing data matrix as follows 0 6 12 18 25 30 0 7 19 26 315664 0 8 13 20 32 8270 1 6 14 21 3085 8959 1 15 27 33 9128 9188 1 9 1634 8485 9093 2 6 28 35 4156 7760 2 10 17 7335 7545 9138 2 11 22 52788728 8962 3 7 2510 4765 8637 8875 3 4653 4744 7541 9175 9198 3 23 23499012 9107 9168 4 7 29 5921 7774 8946 4 7224 8074 8339 8725 9212 4 41698650 8780 9023 9159 5 8 6638 8986 9064 9210 5 2107 7787 8655 9141 9171 524 5939 8507 8906 9173

Secondly, setting up a first cycle with cycle index I with the I rangingfrom 1 to 18, using the data of Ith row in the above table to form asequence and denoting as hexp; nesting a second cycle with cycle index Jwithin the first cycle in which J is ranged from 1 to 256, obtaining therow variable “row” of the $\frac{1}{2}$  LDPC code check matrix usingthe formula row=[(J−1)*18+I], then nesting a third cycle with a cycleindex K under the row variable “row” in the second cycle with the Kranging from 1 to 6, the Kth data of the data sequence hexp beingdenoted as hexp(K), and obtaining the $\frac{1}{2}$  LDPC code checkmatrix according to the following formula:column=Mod [(└hexp(K)/36┘+J−1),256]×36+Mod [hexp(K),36]+1; Wherein thegenerating steps of the $\frac{3}{4}$  LDPC code check matrix is asfollows: Firstly, constructing data matrix as the following table: 0 3 612 16 18 21 24 27 31 34 7494 0 4 10 13 25 28 5233 6498 7018 8358 88059211 0 7 11 19 22 6729 6831 7913 8944 9013 9133 9184 1 3 8 14 17 20 2932 5000 5985 7189 7906 1 9 4612 5523 6456 7879 8487 8952 9081 9129 91649214 1 5 23 26 33 35 7135 8525 8983 9015 9048 9154 2 3 30 3652 4067 51237808 7838 8231 8474 8791 9162 2 35 3774 4310 6827 6917 8264 8416 85428834 9044 9089 2 15 631 1077 6256 7859 8069 8160 8657 8958 9094 9116

Secondly, setting up a first cycle with cycle index I, the I rangingfrom 1 to 9, using the data of Ith row in the above table to form asequence and denoting as hexp; nesting a second cycle with cycle index Jwithin the first cycle in which J is ranged from 1 to 256, obtaining therow variable “row” of the $\frac{3}{4}$  LDPC code check matrix usingthe formula row=[(J−1)*9+I]; nesting a third cycle with a cycle index Kunder the row variable “row” in the second cycle with the K ranging from1 to 12, the Kth data of the data sequence hexp being denoted ashexp(K), and obtaining the $\frac{3}{4}$  LDPC code check matrixaccording to the following formula:column=Mod [(└hexp(K)/36┘+J−1),256]×36+Mod [hexp(K),36]+1.
 40. Thedigital information transmission method according to claim 10, whereinthe bit interleaver uses a 384×360 block interleaver, the bit dataoutputted from the LDPC encoder is written into each row of the blockinterleaver in turn in the order from up to low until the whole blockinterleaver is filled up, then it is read column by column from left toright in turn, and the output of the bit interleaver is aligned with thetime slot.
 41. The digital information transmission method according toclaim 10, wherein the constellation mapping includes one of BPSK, QPSK,16QAM.
 42. The digital information transmission method according toclaim 10, wherein, in the frequency-domain generating step, the 384discrete pilots, 82 continuous pilots and 2610 data sub-carriers aremultiplexed together in each OFDM symbol to form 3076 effectivesub-carriers.
 43. The digital information transmission method accordingto claim 42, wherein the 82 continuous pilots use the 0th, 22th, 78th,92th, 168th, 174th, 244th, 274th, 278th, 344th, 382th, 424th, 426th,496th, 500th, 564th, 608th, 650th, 688th, 712th, 740th, 772th, 846th,848th, 932th, 942th, 950th, 980th, 1012th, 1066th, 1126th, 1158th,1214th, 1244th, 1276th, 1280th, 1326th, 1378th, 1408th, 1508th, 1537th,1538th, 1566th, 1666th, 1736th, 1748th, 1794th, 1798th, 1830th, 1860th,1916th, 1948th, 2008th, 2062th, 2094th, 2124th, 2132th, 2142th, 2226th,2228th, 2302th, 2334th, 2362th, 2386th, 2424th, 2466th, 2510th, 2574th,2578th, 2648th, 2650th, 2692th, 2730th, 2796th, 2800th, 2830th, 2900th,2906th, 2982th, 2996th, 3052th, 3075th sub-carriers in the 3076effective sub-carriers, and the 22th, 78th, 92th, 168th, 174th, 244th,274th, 278th, 344th, 382th, 424th, 426th, 496th, 500th, 564th, 608th,650th, 688th, 712th, 740th, 772th, 846th, 848th, 932th, 942th, 950th,980th, 1012th, 1066th, 1126th, 1158th, 1214th, 1860th, 1916th, 1948th,2008th, 2062th, 2094th, 2124th, 2132th, 2142th, 2226th, 2228th, 2302th,2334th, 2362th, 2386th, 2424th, 2466th, 2510th, 2574th, 2578th, 2648th,2650th, 2692th, 2730th, 2796th, 2800th, 2830th, 2900th, 2906th, 2982th,2996th, 3052th sub-carriers, 64 in total, carry 16 bit systeminformation, the system information comprises 6 bits of time slotnumber, 1 bit of synchronous identification of the byte interleaver, 1bit of control logical channel modify indication and 8 bits beingreserved; the continuous pilots are mapped onto the sub-carriers in aform of 0→√{square root over (2)}/2+√{square root over (2)}/2j,1→−√{square root over (2)}/2−√{square root over (2)}/2j, and the symbolson the same continuous sub-carrier points of the different OFDM symbolsin the same time slot are identical.
 44. The digital informationtransmission method according to claim 42, wherein the sub-carriernumber m corresponding to the discrete pilot in the OFDM symbol is asfollows when the number of the OFDM symbol in each time slot is n:${{{if}\mspace{14mu}{{mod}\left( {n,2} \right)}}=={0\mspace{14mu} m}} = \left\{ {{{\begin{matrix}{{{8\; p} + 1},} & {{p = 0},1,2,\ldots\mspace{14mu},191} \\{{{8p} + 3},} & {{p = 192},193,194,\ldots\mspace{14mu},383}\end{matrix}{if}\mspace{14mu}{{mod}\left( {n,2} \right)}}=={1\mspace{14mu} m}} = \left\{ {\begin{matrix}{{{8p} + 5},} & {{p = 0},1,2,\ldots\mspace{14mu},191} \\{{{8p} + 7},} & {{p = 192},193,194,\ldots\mspace{14mu},383}\end{matrix},} \right.} \right.$ the discrete pilots are all set to1+0j.
 45. The digital information transmission method according to claim10, wherein the generating polynomial of the pseudo-random sequence inthe scrambling step is x12+x11+x8+x6+1; and there are 8 scramblingmodes, and the initial values of the corresponding registers are asfollows respectively: 1) scrambling mode 0: initial value 0000 0000 00012) scrambling mode 1: initial value 0000 1001 0011 3) scrambling mode 2:initial value 0000 0100 1100 4) scrambling mode 3: initial value 00101011 0011 5) scrambling mode 4: initial value 0111 0100 0100 6)scrambling mode 5: initial value 0100 0100 1100 7) scrambling mode 6:initial value 0001 0110 1101 8) scrambling mode 7: initial value 10101011 0011 the pseudo-random sequence is reset at the front end of eachtime slot, all time slots are scrambled by the same pattern.
 46. Thedigital information transmission method according to claim 10, whereinthe IFFT transforming step is as follows: 4096-point IFFT transformationis performed after the 3076 effective sub-carriers are put on thefirst˜1538^(th) and 2558^(th)˜4095^(th) sub-carriers of the 4096sub-carriers.
 47. The digital information transmission method accordingto claim 10, wherein the time-domain framing step is as follows: themodulated OFDM symbol is added with guard intervals, synchronous signal,transmitter identification signal in turn to form a time slot, and then40 time slots are concatenated to form a physical signal frame.